Cooking is a skilled art, and methods are passed down from generation to generation or by word of mouth. The teachings of conventional wisdom, which commonly relate to oven temperature and cooking time, for example, and are annotated with each recipe, are intended to result in a reproducible quality of the finished product. Sometimes however, despite all care and attention, a dinner may be ruined because the meal was overcooked or undercooked, and the tools or monitoring techniques available to avoid this lack sophistication and reliability.
For example, there are many variables involved in determining the right timing for oven cooking. The oven temperature is important but so is the type of food, quantity, thickness, added ingredients, cooking vessel, and presence of a cover such as a lid or a foil wrap. The expected cooking time for a specific food of a specific size and for a chosen oven temperature is often known only under carefully controlled conditions. Small variations in food size, for example, or other cooking parameters will likely invalidate the results of prior experience, so that the process of finding the right cooking time can involve considerable guesswork.
A common method for checking doneness is to cut into the food and visually check the food color and consistency. However, taking the food out of the oven disrupts the cooking process, and cutting can mar the appearance of the dish or result in uneven cooking.
Another method for checking doneness is to insert a cooking thermometer into the food. For continuous monitoring without opening the oven door, more recent cooking thermometers have a temperature probe attached to a monitor or display through a long, heat resistant wire. The wire is led out of the oven and plugged into the display which is conveniently placed nearby. The temperature and time can then be read continuously while the food is cooking.
Commonly used cooking instructions advise the cook to terminate cooking when the internal temperature reaches a certain value, the value depending on food type and desired degree of doneness. Information can also be accessed on the approximate adjustment time required for cooking to compensate for dimensions or weight.
Simply following these instructions may lead to variations in final degree of doneness. In fact, the doneness of a food depends not only on the final temperature but also on the temperature history during the entire cooking period. At the beginning when the temperature is low the food will cook slowly, and during the final stage of the cooking process, when the internal temperature is high, the cooking rate will be much higher. This relationship has not been appreciated, in part because means for measuring and displaying the temperature history have not been available. Thus, even for experienced cooks, cooking quality and doneness is difficult to reproduce and may vary substantially from day to day or place to place.
US Pat. Appl. No. 2011/0052767 to Samples describes a method and system for determining doneness during a cooking process based on a method for accumulating an integral of a meat's internal temperature minus some threshold temperature, where a doneness index EI is calculated from a second order polynomial equation. However, second order polynomial functions, also called parabolic functions have certain limitations in fitting certain sets of data and it remains unclear whether any single such equation could ever be useful in predicting a cooking outcome where the process conditions were not rigidly controlled. This method can only ensure reproducible cooking quality under practically same conditions or for cooking condition having only small variations from the reference condition. Comparative studies shown here include FIGS. 11-12 and FIGS. 8-9 versus FIG. 16.
Thus there is a need in the art for a more reproducible method and apparatus for assessing temperature history in a cooking process and for predicting the required target doneness that will work to the satisfaction of the user regardless of variations in food or process conditions.